Differential gears are generally designed as planetary gearings and predominantly serve to split or distribute a power input onto two drive shafts. Differential gears are most often used as axle differentials in automotive construction. The drive power provided by a drive motor is distributed to the wheel drive shafts of powered wheels via the differential gear. The two wheel drive shafts leading to the wheels are hereby driven with equal torque, i.e. evenly. When driving straight forward, both wheels turn at the same speed. When driving a curve, the rotational speeds of the wheels are different. The axle differential gear allows the rotational speeds to be different. The rotational speeds can adjust freely, only the mean value of the two speeds remains unchanged. In the past, these differentials were widely configured as bevel-gear differentials. Besides this design, differential gears are also configured in the form of spur gear differentials. For these spur gear differentials, the linkage of the output gears functioning as the power output occurs via at least two revolving planets, engaged with one another and thus contradirectionally rotatably coupled, which are typically configured as spur gears.
A spur gear differential that comprises a planet carrier consisting of a spur gear rim and a pair of hub covers axially attached to one side to the spur gear rim is known from U.S. Pat. No. 8,221,278 B2. The hub covers are configured as sheet-formed parts and are axially shaped in such a way that, in the assembled condition, they form a space in which a first and a second output gear, configured in each case as a spur gear, is accommodated. The two output gears are contradirectionally rotatably coupled via revolving planets. The revolving planets form a first revolving planet group and a second revolving planet group. The revolving planets of the first revolving planet group are engaged with the first output gear, the revolving planets of the second revolving planet group are engaged with the second output gear. The coupling of the gears of the revolving planets occurs through their connection under mutual axial displacement of the spur gear arrangement. The sections of the spur gearings, which face away from one another and remain free, engage with the corresponding output gear. The revolving planets are furthermore mounted via bearing bolts. The end sections of the bearing bolts are positioned in locating bores that are configured as such in the hub covers. The spur gear rim, provided to drive the spur gear differential, and the hub covers attached to it form a rigid planet carrier structure. The output gears are axially and radially supported in this planet carrier structure by roller bearings. These roller bearings are configured as cylindrical roller bearings.
A spur gear differential is likewise known from German Patent Application Publication No. DE 10 2007 040 475 A1, in which two inherently identical output gears, configured as spur gears, are contradirectionally rotatably coupled via revolving planet pairs. The engagement zone of these planet pairs is in an area that is axially located between the spur gearings of the output gears.
A spur gear differential is known from U.S. Pat. No. 3,738,192 that exhibits two output gears configured as spur gears, which are contradirectionally rotatably coupled to one another via a revolving planet arrangement. The revolving planet arrangement forms a rim gear. The cogs between the revolving planets forming the rim gear engage, in the same manner as stated with regard to German Patent Application Publication No. DE 10 2007 040 475 A1, in a gearing level between those gearing levels over which the revolving planets engage with the output gears.